As of Tuesday night, 14 of the 16 teams meant to battle it out in the knockout phase have already sealed their berths.
Victor Osimhen, fresh off his African Player of the Year Award win, played a vital role in Napoli's 2-0 victory against SC Braga on Tuesday night.
Napoli were gifted an early lead courtesy of a comical own goal just nine minutes into the game.
Then in the 33rd an unorthodox finish from Osimhen effectively ensured Napoli progressed to the Champions League Round of 16 as runners-up to Group C winners Real Madrid.
For Real Madrid, they maintained their impressive form with a thrilling 3-2 comeback victory against Union Berlin.
This win marked a perfect six-win group stage record for Los Blancos, a feat last achieved during their 2017-18 Champions League triumph.
Man United crash out in disappointing fashion
Manchester United were dealt a painful blow as they succumbed to a 1-0 defeat against Bayern Munich at Old Trafford.
Kingsley Coman's goal sealed United's fate, making them the first Premier League side to finish bottom of their Champions League group on two occasions.
In a contrasting result, FC Copenhagen secured their place in the Round of 16 alongside Bayern Munich through a hard-fought 1-0 victory over Galatasaray.
Other games
Arsenal secured top spot in Group B despite a 1-1 draw against PSV. Meanwhile, Lens defeated Sevilla 2-1 in the other group fixture.
Inter Milan surrendered the top spot in their group after they played out a goalless draw against Real Sociedad.
While both teams had already secured their passage to the Champions League knockout stage before this encounter, it is the Spanish club that finished as Group winners.
As of Tuesday night, 14 of the 16 teams meant to battle it out in the knockout phase have already sealed their berths; leaving just two more slots to be compete for on the last day of action in the group stage on Wednesday.